Overview

• The Science paper analyzed 266 trait-linked markers across ancient horse genomes, identifying nine strongly selected genes and revising early focus away from coat color.
• Selection first targeted behavior, with a ZFPM1-linked region associated with tameness rising around 5,000 years ago.
• An intensive sweep at the GSDMC locus between roughly 4,700 and 4,200 years ago aligns with the emergence of the modern domesticated lineage.
• The GSDMC variant surged to near-fixation within a few centuries and is estimated to have conferred about 20% more offspring to carriers.
• Genetic modification of the GSDMC region in mice produced straighter spines, stronger forelimbs, and enhanced locomotion, supporting a role in ride readiness.